Citrate bridges between mineral platelets in bone.

We provide evidence that citrate anions bridge between mineral platelets in bone and hypothesize that their presence acts to maintain separate platelets with disordered regions between them rather than gradual transformations into larger, more ordered blocks of mineral. To assess this hypothesis, we take as a model for a citrate bridging between layers of calcium phosphate mineral a double salt octacalcium phosphate citrate (OCP-citrate). We use a combination of multinuclear solid-state NMR spectroscopy, powder X-ray diffraction, and first principles electronic structure calculations to propose a quantitative structure for this material, in which citrate anions reside in a hydrated layer, bridging between apatitic layers. To assess the relevance of such a structure in native bone mineral, we present for the first time, to our knowledge, (17)O NMR data on bone and compare them with (17)O NMR data for OCP-citrate and other calcium phosphate minerals relevant to bone. The proposed structural model that we deduce from this work for bone mineral is a layered structure with thin apatitic platelets sandwiched between OCP-citrate-like hydrated layers. Such a structure can explain a number of known structural features of bone mineral: the thin, plate-like morphology of mature bone mineral crystals, the presence of significant quantities of strongly bound water molecules, and the relatively high concentration of hydrogen phosphate as well as the maintenance of a disordered region between mineral platelets.

Solid state NMR of isotope labelled murine fur: a powerful tool to study atomic level keratin structure and treatment effects.

We have prepared mouse fur extensively 13C,15N-labelled in all amino acid types enabling application of 2D solid state NMR techniques which establish covalent and spatial proximities within, and in favorable cases between, residues. 13C double quantum-single quantum correlation and proton driven spin diffusion techniques are particularly useful for resolving certain amino acid types. Unlike 1D experiments on isotopically normal material, the 2D methods allow the chemical shifts of entire spin systems of numerous residue types to be determined, particularly those with one or more distinctively shifted atoms such as Gly, Ser, Thr, Tyr, Phe, Val, Leu, Ile and Pro. Also the partial resolution of the amide signals into two signal envelopes comprising of α-helical, and ß-sheet/random coil components, enables resolution of otherwise overlapped α-carbon signals into two distinct cross peak families corresponding to these respective secondary structural regions. The increase in resolution conferred by extensive labelling offers new opportunities to study the chemical fate and structural environments of specific atom and amino acid types under the influence of commercial processes, and therapeutic or cosmetic treatments.

The well-being of community-dwelling near-centenarians and centenarians in Hong Kong: a qualitative study.

BACKGROUND: Hong Kong has one of the highest life expectancy rankings in the world. The number of centenarians and near-centenarians has been increasing locally and internationally. The relative growth of this population is a topic of immense importance for population and health policy makers. Living long and living well are two overlapping but distinct research topics. We previously conducted a quantitative study on 153 near-centenarians and centenarians to explore a wide range of biopsychosocial correlates of health and "living long". This paper reports a follow-up qualitative study examining the potential correlates of "living well" among near-centenarians and centenarians in Hong Kong. METHODS: Six cognitively, physically, and psychologically sound community-dwelling elders were purposively recruited from a previous quantitative study. Semi-structured interviews were conducted. RESULTS: Four major themes related to living long and well emerged from the responses of the participants: (a) Positive relations with others, (b) Positive events and happiness, (c) Hope for the future, and (d) Positive life attitude. Specifically, we found that having good interpersonal relationships, possessing a collection of positive life events, and maintaining salutary attitudes towards life are considered as important to psychological well-being by long-lived adults in Hong Kong. Most participants perceived their working life as most important to their life history and retired at very old ages. CONCLUSIONS: These findings also shed light on the relationships between health, work, and old age.

Evaluation on the effectiveness on the implementation of WHO caregiver skills training (CST) programme in Hong Kong: a randomised controlled trial protocol.

INTRODUCTION: This protocol delineates the research design and analytical framework used to evaluate the effectiveness of the WHO-CST (CST, caregiver skills training) in Hong Kong. The WHO-CST aims to enhance the caregiver skills of parents of children with potential autism spectrum disorders (ASD) and/or developmental delays. METHODS AND ANALYSIS: In this study, 130 eligible caregiver-child dyads were recruited and randomly assigned to the experimental and wait-list-control groups. A randomised controlled trial design was adopted to compare the changes between the two groups regarding caregivers' skills, knowledge and practices when interacting with their children with impairments due to ASD. Assessments were conducted before, immediately after and 1 month after the completion of the WHO-CST programme. The primary measurement tool was the joint engagement rating inventory developed by WHO experts to gauge how parents engage their children. A 10-min video recording of their dyadic interaction and behaviours in a defined play setting was used for the measurement. A set of other measurements of caregivers' knowledge, confidence and experience of using the caregiving skills were also measured. ETHICS AND DISSEMINATION: Ethics approval was received from the Human Research Ethics Committee (EA1901033), The University of Hong Kong. The final findings of this study will be disseminated through public reports, peer-reviewed publication or at a conference launched for the WHO-CST programme. TRIAL REGISTRATION NUMBER: ChiCTR2000034585.

Effectiveness of pelvic floor muscle training alone or combined with either a novel biofeedback device or conventional biofeedback for improving stress urinary incontinence: A randomized controlled pilot trial.

PURPOSE: To (i) compare the acceptance of a newly developed, novel biofeedback device (PelviSense) with that of conventional biofeedback (CB) using an intravaginal probe for the treatment of stress urinary incontinence (SUI) in women, (ii) examine the feasibility and safety of using the PelviSense device as a pelvic floor muscle (PFM) training (PFMT) adjunct, and (iii) compare the PFMT adherence and effectiveness of CB, the PelviSense device, with PFMT alone for women with SUI. METHODS: An assessor-blinded, three-arm, randomized controlled pilot trial was conducted among 51 women with SUI. Women were randomly allocated to one of three study groups (PelviSense-assisted PFMT, CB-assisted PFMT, or PFMT alone [control]). Outcome measures included the International Consultation on Incontinence Questionnaire-Short Form, the 1-h pad test, and the Modified Oxford Scale. RESULTS: Participants in the PelviSense-assisted PFMT group expressed good device acceptance. PFMT adherence was greater in the PelviSense-assisted PFMT group than in the unassisted or CB-assisted PFMT groups. Between-groups analysis revealed significant effects on improved SUI symptoms, urine loss severity, and PFM strength for the PelviSense-assisted PFMT group compared with the CB-assisted and PFMT alone groups. CONCLUSIONS: The pilot trial results demonstrated moderate to high PFMT adherence in the PelviSense-assisted PFMT group and supported the safety of using the PelviSense device. The preliminary results of the pilot trial showed that PelviSense-assisted PFMT was more effective for reducing SUI symptoms among women than unassisted or CB-assisted PFMT. TRIAL REGISTRATION: This trial was registered in http://ClinicalTrials.gov (reference number: NCT04638348) before the recruitment of the first participant.

Dehydration and crystallization of amorphous calcium carbonate in solution and in air.

The mechanisms by which amorphous intermediates transform into crystalline materials are poorly understood. Currently, attracting enormous interest is the crystallization of amorphous calcium carbonate, a key intermediary in synthetic, biological and environmental systems. Here we attempt to unify many contrasting and apparently contradictory studies by investigating this process in detail. We show that amorphous calcium carbonate can dehydrate before crystallizing, both in solution and in air, while thermal analyses and solid-state nuclear magnetic resonance measurements reveal that its water is present in distinct environments. Loss of the final water fraction--comprising less than 15% of the total--then triggers crystallization. The high activation energy of this step suggests that it occurs by partial dissolution/recrystallization, mediated by surface water, and the majority of the particle then crystallizes by a solid-state transformation. Such mechanisms are likely to be widespread in solid-state reactions and their characterization will facilitate greater control over these processes.

NMR spectroscopy of native and in vitro tissues implicates polyADP ribose in biomineralization.

Nuclear magnetic resonance (NMR) spectroscopy is useful to determine molecular structure in tissues grown in vitro only if their fidelity, relative to native tissue, can be established. Here, we use multidimensional NMR spectra of animal and in vitro model tissues as fingerprints of their respective molecular structures, allowing us to compare the intact tissues at atomic length scales. To obtain spectra from animal tissues, we developed a heavy mouse enriched by about 20% in the NMR-active isotopes carbon-13 and nitrogen-15. The resulting spectra allowed us to refine an in vitro model of developing bone and to probe its detailed structure. The identification of an unexpected molecule, poly(adenosine diphosphate ribose), that may be implicated in calcification of the bone matrix, illustrates the analytical power of this approach.